Method and apparatus for positioning a strip of material along the seam of an advancing cable sheath



May 24, 1966 M. R. DEMBIAK ET AL METHOD AND APPARATUS FOR POSITIONING A STRIP OF MA Filed Nov. 5 1963 TERIAL ALONG THE SEAM OF AN ADVANCING CABLE SHEATH 4 Sheets-Sheet l INVE'N 'T'UR'E I77. 1?. .UE/77E/F7K /77. RULu/JN M 7 [I /veg May 24, 1966 R DEMBIAK ET AL 3,252,216

METHOD AND APPARATUS FOR POSITIONING A STRIP OF MATERIAL ALONG THE SEAM OF AN ADVANCING CABLE SHEATH Filed Nov. 5 1963 4 Sheets-Sheet 2 May 24, 1966 D K ET AL 3,252,216

METHOD AND APPARATUS FOR POSITIONING A STRIP OF MATERIAL ALONG THE SEAM OF AN ADVANCING CABLE SHEATH Filed Nov. 5, 1963 4 Sheets-Sheet 5 May 24, 1966 M R DE I K ET AL 3,252,216

METHOD AND APPARATUS FOR POSITIONING A STRIP OF MATERIAL ALONG THE SEAM OF AN ADVANCING CABLE SHEATH Filed Nov. 5, 1963 4 Sheets-Sheet 4 United States Patent 3 252.216 METHOD AND APPAlATUS FQR PUSITIONENG A STRIP 0F MATERIAL ALONG THE SEAM 0F AN ADVANClNG CABLE SHEATH Matthew R. Dembiak, Passaic, and Milton Rowan, Elizabeth, N.J., assignors to Western Electric Company, In-

corporated, New York, N.Y., a corporation of New York Filed Nov. 5, 1963, Ser. No. 321,574 Claims. (Cl. 29-464) This invention relates to cable manufacture and particularly to a method and apparatus for automatically centering a strip of insulating material over the seam of a longitudinally folded metallic sheath enclosing a cable core.

In the cable art, cables of the Alpeth type comprise a cable core having a flat or corrugated metallic sheath surrounding the core and an outer jacket of an extruded thermoplastic insulating material surrounding the metallic sheath. When the metallic sheath, usually of aluminum, is not soldered or otherwise joined at the overlap, it tends to spring open after leaving the sheath forming tool, cutting into the plastic sheath which is extruded thereover. This causes an undesirable reduction in the thickness of the insulating jacket at the seam. As a result, it has become common practice to place a thin strip of insulating tape axially along the corrugated aluminum seam to prevent the metallic sheath from opening and to achieve a uniform thickness of insulating material about the cable. Since the sheathed core is fed directly to an extruder, the tape is held in place over the seam by the extruded plastic in a manner similar to that disclosed in Patent 3,087,007 to L. Jachimowicz.

The present solution, however, has not been entirely satisfactory due to the fact that the metallic seam tends to shift after it has been advanced through a former of the type disclosed in Patent 2,764,214 to E. W. Reynolds et al. by conventional feed means and prior to the placement of tape along the seam. To insure accurate alignment over the seam, the lay of the tape must be constantly adjusted. This requires frequent operator attention, for if no allowance is made for seam shifting, the completed cable will be unsatisfactory due to the misalignment of the tape with respect to the seam.

Accordingly, an object of this invention is to provide an improved cable construction wherein an insulating tape is automatically centered along the seam of a sheath encircling the cable.

Another object of this invention is to provide a means for automatically centering an insulating tape over the seam on an overlapped metal sheath prior to extrusion of an outer plastic jacket in order to provide a substantially uniform thickness of insulating material about the sheath.

A more specific object of this invention is to provide means for intermittently detecting the position of a shifting seam on a metal sheath and automatically centering a strip of insulating material over the seam.

With these and other objects and advantages in view, the present invention contemplates an apparatus for antomatically centering a strip of insulating tape over the metallic seam on cables of the Alpeth type which comprises a seam detector and a tape centering mechanism actuated by signals from the detector to adjust the feed of the tape to maintain it continuously in the same relative position with respect to the cable seam. The seam detector includes an oscillating sensing device movable about the cable axis to intermittently sense the position of the seam and to transmit directional signals to a reversible motor included in the tape centering mechanism. The motor moves the tape feeding mechanism angularly rection of the tape position is required.

As the tape is driven towards alignment with the seam, a signal is ted back from the centering mechanism to adjust the position of the sensing device relative to the seam. The angular movement of the sensing device is proportional to the movement of the centering mechanism so that the new tape position is compared with the seam location during the next sensing interval. The tape is thereby brought into alignment with the sheath seam by sequentially detecting the seam position, adjusting the tape feed in the proper direction and feeding back a signal to the detecting means indicating the extent of the adjustment. The cycle is repeated until the tape is properly positioned over the seam. When this objective is achieved, the sensing device fails to send an actuating .signal to the centering mechanism during its period of intermittent operation.

These and other objects and advantages of the present invention will be apparent from the following detailed description when considered in conjunction with the following drawings, wherein:

FIG. 1 shows a side view of the apparatus including the seam detector and tape centering mechanism;

FIG. 2 illustrates a front view of the seam detector taken along the line 2-2 of FIG. 1;

FIG. 3 shows a side view of the seam detector, parts of which are broken away to illustrate the operation thereof;

FIG. 4 is a top view of the tape centering mechanism taken along the line 44 of FIG. I; and

FIG. 5 is a schematic illustration of the control circuit for the apparatus.

With reference to FIG. 1 of the drawings, an apparatus for automatically centering a strip of insulating tape 10 over the butted or overlapped seam 20 on corrugated or flat metallic cable sheaths, such as the aluminum sheath 30 on A-lpeth cables, comprises a seam detector 40 and a tape centering mechanism 50. The detector 40 intermittently checks the position of the seam 20 and when necessary actuates the centering mechanism 50 to adjust the feed of insulating tape 10 as the sheathed core 35 leaves a metal former (not shown) prior to sheath binding and extrusion of an outer plastic jacket thereover. The tape 10 is thereby positioned in a substantially constant position relative to the cable seam 20 to achieve a uniform thickness of insulating material about the cable and to prevent weak spots from occuring in the extruded outer jacket of thermoplastic material. In a typical embodiment, the tape 10 would comprise a material such as polyethylene terephthalate known by the trademark Mylar, a cellulose acetate, or a laminate combining several insulating materials in a structure approximately 5 mils in thickness.

The seam detector 40, illustrated in FIGS. 1, 2 and 3 includes an oscillatable tube 11 having an aperture 15 through which the sheathed cable core passes after a metal sheath-forming operation and a cam ring 12 concentrically mounted thereabout and attached to the tube 11 by an adjustable spring-urged plunger 13 mounted in a housing 14. The tube 11 is journaled in bearings 61 within a housing 16 located on the upper portion of main support 17. A motor 18 is connected to a member 24 which is mounted perpendicularly to the support 17 a short distance above the base 25. The motor 18 continuously oscillates the tube 11 through an angle of approximately by means of an adjustable crank linkage 19, see FIG. 2, which includes a crank 22 and .an eccentric 23 connected to the drive shaft 21 of the motor 18. The 120 oscillation allows a safe margin of operation since the seam divergence from a normal path is usually much less than this amount. I

In its movement about the core axis the tube 11 carries along the frictionally engaged cam ring 12 until a wiper 26 pivotally mounted to the ring 12 at one end 27 and held in contact with the metallic sheath 30 at the other end 28 engages the seam 20. The wiper end 28 extends at right angles to the principal axis of the wiper 26 in order to contact the seam 20 under urging of a spring 29 mounted intermediate its ends 27 and 28 at point 31. The other end of spring 29 is secured to the cam ring 12 at 32. This arrangement prevents further movement of the ring 12 in a given direction while the tube 11 continues its oscillatory motion. When the tube 11 moves in the opposite direction, plunger 13 picks up the ring 12 which was held by the wiper 26 and carries it along, the cycle being repeated continuously. To permit rotational movement the cam ring is journaled in bearings 60 about the tube 11.

At the extreme end of the tubes arc of travel in either direction, a cam 55 attached to eccentric 23 and operating off the shaft 21 of motor 18, closes a pulsing switch 45 momentarily. Depending upon seam location, either a left or right directional switch 33 or 34 respectively, may be actuated during the pulsing interval by a corresponding high surface 37 of the cam ring '12 while the low surface 36 is positioned opposite the inoperative switch. When actuated, the switches 33 and 34 operate the tape centering mechanism 50, driving the guide rollers 51 and 52 a prescribed distance see FIG. 4, to one side or theother of the seam 20 as required. The switches 33 and 34 are conventional plunger-type switches .mounted to a right-angular arm 38 which is connected to an apertured mounting 39 rotatably disposed about the tube 11.

When the tape is centered over the seam 20, neither switch 33 nor 34 will be actuated during the pulsing interval since the cam dwell 41 will be positioned opposite the switches 33 and 34 at the moment of pulsing. When the tape centering mechanism 50 shifts the tape 10, as will be described later, it also drives a flexible shaft 42 which rotates the directional switches 33 and 34 through a chain and sprocket arrangement. The flexible shaft 42 terminates in a holder 43 attached to housing 16 on support 17 and includes a drive shaft 44 extending therefrom having a relatively small drive sprocket 46 mounted on one end. A larger driven sprocket 47 is operatively connected thereto by a chain 48. It is to be noted that sprocket 47 is attached to mounting 39 which is journaled in anti-friction bearings 65 and is connected to the rotatable arm 37 including the switches 33 and 34. The rotation of the arm 38 due to this feedback having a member 54 adjustably mounted thereto. The.

member 54 includes an upper platform portion 57 extending substantially parallel to the axis of the cable core 35, a downwardly extending motor mounting 62 and a lower tubular portion 58 adjustably connected to support 56 by screw means 59. A reversible motor 53 actuated by pulse signals from the seam detector 40 is secured to mounting 62. The drive shaft 63 of motor 53 is journaled in a housing 66 mounted on a platform 67 which is attached to motor mounting 62. The flexible shaft 42 is connected to the shaft 63 within housing 66 in a conventional manner for actuation by the motor 53.

A drive sprocket 64 is located intermediate the ends of drive shaft 63 to transmit the reversible motion of the motor 53 to an eccentric 68 through a chain 69 and sprocket 71. The sprocket 71 drives a shaft 72 which is journaled in member 73 at an intermediate portion 74 and connected at one end 76 to the eccentric 68 and to the sprocket 71 at its other end 77. A linkage 78 is adjustably mounted to the eccentric 68 at 79 to trans- 4 mit the movement of the eccentric 68 to guide rollers 51 and 52.

The linkage 78 essentially comprises a rod portion 83 threaded at ends 8 1 and 82 and two similar members 84 and 86 each having an internally threaded portion 87 to engage the threaded ends of the rod 83 and an apertured bearing section 88 for mounting purposes. In the illustrated embodiment, the members 84 and 86 are mounted about ball joints on shafts 72 and 89. The latter shaft 89 is connected to tape-aligning roller 51 through element 91.

Elements 91 and 92 are pivotally mounted to vertical supports 93 and 94 respectively, which are positioned within apertures in the upper portion 57 of member 54. A linkage 96 similar to the previously described linkage 78 joins elements 91 and 92 for simultaneous movement of a predetermined amount about the sheathed core 35 upon actuation of the motor 53. The linkage 96 is adjustably mounted at its ends 97 within slots 9.8 to insure that the required movement is imparted to each roller 51 and 52 so that it is immaterial whether the tape feed proceeds over roller 51 or 52. The rollers 51 and 52 are independently adjustable to maintain the proper alignment of tape exhausted tape reel (not shown) is replaced.

Two indicating scales, 101 and 102, are provided as shown in FIGS. 1 and 2 in order to position the switches 33 and 34 and the rollers 51 and 52 to obtain the desired relationship between the rotational movement of the switches and the angular displacement of the rollers. In the seam detector 40, scale 101 is connected to mounting 39 which includes directional switches 33 and 34 on arm 38 while indicator 103 is mounted on stationary housing 16. The scale 102 in mechanism 50 is connected to the sprocket 71 while the indicator 104 is mounted on member 73. By adjusting the scale readings during set-up, a rapid correlation is obtained between cam position, indicative of seam location, and roller position which determines the direction of the tape feed.

FIG. 5 is a schematic representation of the electrical control circuit which normally operates off a volt A.C., 60 cycle source 105. When start switch 108 is operated, motor 18 is activated to intermittently close pulsing switch 45 as previously described. If the tape 10 is improperly aligned with the seam 20, reversing motor 53 will be activated by either switch 33 or 34 to drive the tape feed to the left or right of the core axis as required.

It is to be understood that the above described arrange ments are simply illustrative of the application of the principles of the invention. For instance, other sensing devices such as a photoelectric arrangement might be substituted for the particular mechanical sensing device disclosed herein and other tape applying means such as a guide oscillatory about the core axis by a reversible motor might be employed. Numerous other arrangements may, of course, be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is: v

1. An apparatus for positioning a strip of material along a seam on a cable sheath comprising:

a sensing device,

means for oscillating the sensing device about the axis of the sheath to detect the seam position, I

a reversible motor,

means for transmitting directional signals from the sensing device to the reversible motor, and

means for applying the strip of material over the seam,

said means being coupled to the reversible motor and moved a predetermined distance by the motor with relation to the cable axis in response to the directional signals when correction of the position of the strip is required.

2. An apparatus for automatically centering an insulating tape over the seam on a moving metal sheath surrounding a cable core comprising:

a tube having an aperture through which the sheathed core is moved,

a cam ring mounted about the tube for movement therewith, a wiper mounted to the cam ring at one end and positioned to engage the sheath with the other end,

means for continuously oscillating the tube about the sheath so that the wiper engages the seam freeing the cam ring from rotation with the tube and establishing a relationship between the position of the cam ring and the position of the seam,

pulsing means positioned to engage the cam ring to generate a signal indicative of the seam position, means for orienting the pulsing means with reference to the cam ring,

a tape centering mechanism for applying the tape to the seam, reversible drive means for receiving the signal from the pulsing means to drive the tape centering mechanism angularly with relationto the axis of the sheathed core when the tape is not centered thereover, and

means for transmitting a signal to the orienting means proportional to the amount of tape shifting to orient the pulsing means for sending further signals.

3. An apparatus in accordance with claim 2 wherein the means for transmitting a signal to the orienting means comprises:

a flexible shaft connected to the reversible drive means,

a driving sprocket connected to said flexible shaft,

a driven sprocket mounted to the tube, and

a chain connecting the sprockets such that actuation of the reversible drive means by the pulsing means causes a proportional feedback signal through the flexible shaft, positioning the pulsing means with relation to the cam ring through the chain and sprocket arrangement.

4. An apparatus in accordance with claim 2 further including:

gating means becoming operative as the oscillating t'ube reaches the apex of its arc of travel permitting the pulsing means to send an intermittent signal to the reversible drive means indicative of the seam position. 5. An apparatus in accordance with claim 2 wherein the tape centering mechanism comprises:

first and second rollers angularly movable about the axis of the sheathed core, and

means connecting said rollers for simultaneous movement upon actuation by the reversible drive means to position a strip of material over the cable seam.

6. An apparatus for positioning a strip of tape over the seam on an advancing metal cable sheath which tends to shift comprising:

a sensing device,

means for continuously moving the sensing device about the sheath axis to detect the seam position,

switching means intermittently operable by the means for moving the sensing device,

reversible drive means,

'6 means responsive to the sensing device for sending a signal to the reversible drive means through the intermittently operable switching means causing said means to drive in one direction or the other depending upon the seam position, and a tape centering mechanism driven by the reversible drive means for guiding a strip of tape over the cable seam.

7. An apparatus in accordance with claim 6 further including:

means for feeding back a signal to the sensing device proportional to the movement of the tape centering mechanism to move said sensing device for further seam detecting operations'with relation to the new tape position, and

means facilitating establishment of a desired relationship between the sensing device and the tape centering mechanism.

8. An apparatus for applying a strip of tape in a predetermined location along a moving cable assembly comprising:

a sensing device for determining the position of the cable assembly location to which tape is to be' applied, tape applying means for feeding a strip of tape along the cable assembly,

a control means operable to change the direction of feed of the tape applying means, and

means for intermittently transmitting a signal from the sensing device to the control means to direct the tape feed over the predetermined cable assembly location. 9. The method of positioning a strip of material along the seam of an advancing cable sheath comprising the steps of:

applying a strip of material along the seam of the advancing cable sheath, detecting the position of the seam about the axis of the advancing cable sheath before the application of the strip of material,

transmitting signals to a control means in accordance with the instantaneous position of the seam, and moving the strip of material about the axis of the advancing sheath in response to said signals.

10. The method of positioning a strip of material along the seam of an advancing cable sheath in accordance with claim 9 further including the step of:

altering the detecting operation in accordance with the extent of strip movement about the axis of the sheath to facilitate further detecting operations.

References Cited by the Examiner UNITED STATES PATENTS 2,697,769 12/1954 Carpenter 2196 2,936,357 5/1960 Crawford 156- 54 X 2,990,173 6/1961 Melville 156361 X 3,087,007 4/ 1963 Jachimowicz 17 41 10 3,137,120 6/1964 Budenbender 156-545 X EARL M. BERGERT, Primary Examiner.

JOSEPH REBOLD, Examiner.

jP. DIER, Assistant Examiner. 

1. AN APPARATUS FOR POSITIONING A STRIP OF MATERIAL ALONG A SEAM ON A CABLE SHEATH COMPRISING: A SENSING DEVICE, MEANS FOR OSCILLATING THE SENSING DEVICE ABOUT THE AXIS OF THE SHEATH TO DETECT THE SEAM POSITION, A REVERSIBLE MOTOR, MEANS FOR TRANSMITTING DIRECTIONAL SIGNALS FROM THE SENSING DEVICE TO THE REVERSIBLE MOTOR, AND MEANS FOR APPLYING THE STRIP OF MATERIAL OVER THE SEAM, SAID MEANS BEING COUPLED TO THE REVERSIBLE MOTOR AND MOVED A PREDETERMINED DISTANCE BY THE MOTOR WITH RELATION TO THE CABLE AXIS IN RESPONSE TO THE DIRECTIONAL SIGNALS WHEN CORRECTION OF THE POSITION OF THE STRIP IS REQUIRED. 